1. Field of the Invention
The present invention relates to a cleaning agent composition and a cleaning method employing the same. The cleaning agent composition and the cleaning method are effective for removing soldering flux applied during manufacturing processes of electric and electronic components and appliances, waxes applied for fastening works on jigs used in cutting or grinding process of the works, or any oils applied in press-working process. In more detail, the present invention is concerned with a cleaning agent composition for cleaning in particular, metal surfaces such as printed circuit boards, electronic components used in electric or electronic appliances and machine-worked components, and a cleaning method employing the cleaning agent composition.
2. Description of the Related Art
Heretofore, chlorofluorocarbons (hereinafter referred to as "CFCs") and chlorine-containing organic solvents represented by 1, 1, 1-trichloroethane, trichloroethylene, tetrachloroethylene, and dichloromethane have been employed as the cleaning agents for removing the residual soldering flux and the machine oil at the removal step.
It is however of urgent necessity to refrain from the use of these chlorine-containing organic solvents from the standpoint of the recently increasing global environmental concern. For instance, the CFCs and 1,1,1-trichloroethane have recently been considered responsible for destructing the ozone layer of the stratosphere surrounding the globe. The other chlorine-containing organic solvents, for instance, trichloroethylene, tetrachloroethylene and dichloromethane are typical carcinogenic substances, and have been contributing to contaminating underground water because they are liable to infiltrate into the ground soil.
As the cleaning agent composition that can be replaced with these chlorine-containing organic solvents, a cleaning agent composition consisting mainly of a glycol ether compound has specifically been proposed (Japanese Laid-Open Patent Publication No. Hei 3-162,496, Japanese Examined Patent Publication No. Hei 5-40,000, and so on). In a cleaning process using one of these cleaning agent compositions, it is generally required to perform an additional second step of removing the cleaning agent with tap water or deionized water from the object to be cleaned.
The glycol ether compounds disclosed in the above-mentioned Japanese Laid-Open Patent Publication No. Hei 3-162,496 are ethylene glycol compounds which are employed after mixed with water or with a surfactant in order to increase their cleaning ability and intermiscibility with water employed in the second step. Further, the cleaning agent composition disclosed in the Japanese Examined Patent Publication No. Hei 5-40,000 contains glycol ether compounds and it requires to be added with a nonionic surfactant and a phosphate ester on the same ground as that disclosed in the Japanese Laid-Open Patent Publication No. Hei 3-162,496. The ethylene glycol compounds however have a disadvantage that they cause a hazardous effects on human body. Moreover, when mixed with the surfactant, they are particularly difficult in disposal of waste water of their admixture with tap water or deionized water used in the second step.
In addition, the surfactants have been found by the present inventors to exert a serious influence on an insulation reliability of the electric or electronic appliances if they are allowed to remain in such appliances.